Method of inspissating liquids



E. WIRTH-FREY.

METHOD OF INSPISSATING LIQUIDS;

APPLICATION FILED MAR. 15' 919.

1 ,405,244=. Patented Jan. 3 1, 1922.

[Zak r 0137C 5 UNITED STATES ELIAS WIBTH-FREY, OF AARAU, SWITZERLAND.

METHOD OF INSPISSATING LIQUIDS.

Specification of Letters Patent. Patented Jan gl 1922 Application filedMareh 15, 1919. Serial No. 282,980.

TOIQZZ whom it may concem Be it known that I, ELIAS WIRTH-FREY, a citizen of the Swiss Confederation, and residing at Aarau, Switzerland, have invented certain new and useful Improvements in Methods of Inspissating Liquids, of which the following is a specification.

The present invention has reference to a new and improved method or process forthickening liquid by evaporation, and relates more specifically to an inspissuting operation in which the steam or vapor risingfrom the liquid under treatment is drawn ofi, is compressed, and is then used over again as heating medium.

According to my invention the steam issuing from the compressor is first caused.

to act on the highest concentrated portion of the liquid and subsequently on the rest of it of lower concentration. The operation may be. ca-rried-th ough in such manner that the working st am fresh from the compressor is introduced first into the rearmost of a plurality of serially intercommunicating vessels, and is then conducted in parallel or multiple arrangement into the other vessels. If, by way of example, in an inspissating installation four boilers I, II, III and IV are arranged in series, the heating steam coming fresh from the compressof 'may be introduced first into the rearmost boiler IV, and from there in two parallel conduits simultaneously into the boilers II and I; or it may be led, after having acted on the liquid in boiler IV, in three, relative to the steam course parallelly disposed conduits simultaneously into the boilers III, II and I.

It is well known that with increasing concentration of a liquid solution, for instance lye, its boiling point is raised and that to allow for this the working steam must correspondingly be placed under a steadily increasing pressure and thus must be compressed to an increasingly higher tempera ture. If for compressing a centrifugal compressor is used, either an increase in the number of the Working .steps or an increase in the rotary speed is called for. The first expedient would require an expensive construction, and the second can only with difficulty be resorted to where the rotary compressor is driven by a three phase-motor.

It is in such cases that the present invention offers great advantages, as also in inspissating plants which operate continuously and 1n which in one part of the boilers the solution still shows a weak concentration whilst in the other part already a more advanced state of concentration obtains, and

it is here that my invention efl'ectively deals with the touched-on phenomenon that the more strongly concentrated solution pos sesses a higher boiling point and therefore requires a heating medium of higher temperature for transferring a certain number of calories in a given pegiod of time, than does a portion of the solution still in the initial weakly concentrated state.

My invention will best be understood when described in connection with the accompanying sheet of drawings, in which is shown in diagrammatic section an apparatus oper-- ating on three serially connected boilers.

In the arrangement shown in the drawing the boilers 21, 22 and 23 are connected in series. The lye enters the vessel 21 through pipe 24, passes through pipe 25 to the next vessel 22, and then through pipe 26 into the last 'vessel 23, from where it finally flows off in conoentrated'state through v pipe 27. The lye steam forming in. the three boilers is drawn out of them by the centrifugal compressor 29 through the common conduit 28, is compressed and is then sent through pipe 30- to the rearmost boiler 23,

wherein the heating steam gives off part of its heat. The steam in the pipe 30 will be in superheated state due to the preceding compression, but its degree of superheat, obviously, decreases during its passage through the boiler 23, so that the steam issuing from this boiler will be found to be only slightly superheated or even already saturated. From the vessel 23 the one half of the heating medium passes through pipe '31 into the heating chamber of the boiler 22, whilst the other half passes through pipe 32 into the boiler 21, where it condenses completely. The condensate runs off from the boilers 22 and 21 through the pipes 33 and 34 respectively.

Back of the heating chamber of the boiler 23 the steam may be passed through a water separator 35 prior to being inducted into the boilers 22 and 21.

To compensate for loss of'heat during the operation, fresh steam may be introduced into the boiler 1, but where the boilers and the pipes for conducting the heating medium emcl the liquid to be treated are well insuleted, the lcss of heat will be practically nil.

What l claim is:

The method of inspissating liquids in a, plurality of serially intact-communicating concentrating vessels, which consists in causing the steam supplied by a compressor to act first entirely on the contents \of the last one in the series of vessels and then 10 simultnneeusly in parallel arrangement on the contents of the other vessels.

' ELIAS WlRlH-FREY. Witnesses:

lFmnnmcK NAsennR, H, 'l, STEHLIN. 

